244 DISSERTJTION, &c. 



neceflary to the funcSlions of the animal oeconomy, fuch as what 

 are called vital fpirits, the exiltence of which is fuppofed, with 

 Tome degree of probability, without our being able tc fay what 

 they are. This idea appears the more likely, as it is known that 

 the diffolvin^, power of air is not confined to water alone, but 

 is extended to many other bodies. If then my conjeif^ure is 

 founded, there appears to me, Sir, a very eafy way to prevent 

 this fort of difeafe ; for in fa(fl it is one, although but flight 

 and of little confequence ; we have only to give back to the 

 air the humidity which the frofl: had robbed it of, which may 

 be done, either by promoting the evaporation of a certain quan- 

 tity of water in the room, or, what will be a much more con- 

 venient and fhorter mode of doing it, to hang up a cloth of a 

 proper fize, dipped in water, and wetted from time to time^ — 

 I fubmit. Sir, thefe conjedlures to yovir judgment ; as all that 

 regards the impreflion which, in length of time, may be made 

 on the human body, by a very dry and a very drying air, falls 

 more immediately into your line as a Phyfician, than into that 

 of your moft obedient fervant, 



iEpiNUS. 



You may make what ufe you pleafe of this letter, and give 

 it the fame deftination as the firft, if you think proper. 



EiXD OF PAPERS OF THE PHTSICAL CLASS. 



